Cost per install
calculator.
Your CPI counts every install. This calculator also shows what each extra install cost, after taking out the people who would have downloaded your app anyway.
Cost per extra install—
Naive cost per install—
Extra installs from ads—
Lift over baseline—
Installs you'd have had anyway—
How to fill it in
- Ad spend is the total for the campaign over the period, from Meta Ads Manager or any ad network.
- Installs per day before launch is your average over the week before the campaign started, in the countries it targets. Find it in App Store Connect under Sales and Trends, filtered by territory.
- Installs per day during campaign is the same figure while the campaign ran.
Which number should I use?
Naive CPI is what most dashboards show: spend divided by installs. It's fine for comparing ad networks with each other, but it always looks better than reality, because it credits the ads with your organic downloads too.
Cost per extra install divides spend by the installs above your baseline. Compare it against what an install is worth to you (your average revenue per user over a sensible window). If it's lower, scale. If it's higher, the campaign is buying installs at a loss, whatever the naive CPI says.
The full method, and when it breaks down, is in measuring incremental installs.
Skip the spreadsheet
Ads Manager does this for every Meta campaign automatically, using real App Store Connect installs for exactly the countries each campaign targets, and flags campaigns whose baseline overlaps another one.
Questions
What's a good cost per install for an iOS app?
It depends on the category and country more than anything. Rather than benchmark against averages, compare your cost per extra install to what a user is worth to you. That's the only threshold that decides whether a campaign pays back.
Why is cost per extra install higher than CPI?
Because it leaves out installs that would have happened without the ad. If your baseline is zero, the two are equal.
What if installs dropped during the campaign?
Then the calculator shows no lift. Either the campaign isn't working, or something else (seasonality, a ranking drop) hid its effect. Look at a longer period before deciding.
Know what's working.
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